Drive circuit

Abstract

A drive circuit includes a transformer T 1 having a primary winding N 1 to which a drive signal P 1 is applied and a first secondary winding N 2 , a first switching element Q 1 , a first capacitor C 3 connected between a first end of the first secondary winding of the transformer and a control terminal of the first switching element, and a first series circuit including a first zener diode ZN 1 and a second zener diode ZN 2 , a cathode of the first zener diode being connected to a connection point of the first capacitor and first switching element, a cathode of the second zener diode being connected to a second end of the first secondary winding.

1 . A drive circuit comprising:
 a transformer (T 1 ) having a primary winding (N 1 ) to which a drive signal (P 1 ) is applied and at least one secondary winding including a first secondary winding (N 2 );   a first switching element (Q 1 ) configured to be turned on/off in response to a signal outputted from the first secondary winding of the transformer;   a first capacitor (C 3 ) connected between a first end of the first secondary winding of the transformer and a control terminal of the first switching element; and   a first series circuit including a first zener diode (ZN 1 ) and a second zener diode (ZN 2 ), a cathode of the first zener diode being connected to a connection point of the first capacitor and first switching element, and a cathode of the second zener diode being connected to a second end of the first secondary winding.   
     
     
         2 . The drive circuit according to  claim 1 , further comprising
 a first diode connected to both end of the first capacitor in parallel with the first capacitor.   
     
     
         3 . The drive circuit according to  claim 2 , further comprising:
 a second secondary winding (N 3 ) provided for the transformer;   a second switching element (Q 2 ) connected in series with the first switching element;   a second capacitor (C 4 ) connected between a first end of the second secondary winding of the transformer and a control terminal of the second switching element; and   a second series circuit including a third zener diode (ZN 3 ) and a fourth zener diode (ZN 4 ), a cathode of the third zener diode being connected to a connection point of the second capacitor and second switching element, a cathode of the fourth zener diode being connected to a second end of the second secondary winding of the transformer.   
     
     
         4 . The drive circuit of  claim 3 , further comprising
 a second diode (D 2 ) connected to both ends of the second capacitor in parallel with the second capacitor.